Electric lock



G. W. WATSON Der; 18, 1928.

ELECTRIC LOCK Filed Oct. l0, 1927 Z 3 6767/' a QoL/5%.

4 @315.5 A C ma A. H

Patented Dec. 18, 1928. i

UNITED@` STATES masia GLENN W. WATSON', 0F DETROIT, MICHIGAN.

ELECTRIC LOQK. I

Application*tiledl October `10, 1927. Serial No. 225,046.

yThe present invention pertains to a no vel lock controlled by a key which, 1n addition to its usual functionis modified to control an auxiliary locking mechanism which may be associatedwith the lock or with some independent device. n

The principal object of the invention 1s to provi-de a lock which cannot unauthorizedly be opened by mere duplication of the key. r1`here is provided an auxiliary locking device between the relatively movable parts of the lock proper,d and the release of the auxiliary 'device depends on the closing .of a clrcuit governed by one or more conducting paths arbitrarily formed within the key. 1t 1s preferredthat the circuit inclu-de at least two of the tumblers of the lock, and the bridgmg of these tumblers. depends on the formation of a conducting path in the key between the notches or recesses thereof corresponding to said tumblers inthe circuit. Such a device `is ofv unlimited application an'd may infact 4 4 of Figure 1 Fig. 5 is an edge view of the key; Fig. 6 is a detail end view with the barrel removed;

Figf7 is a transverse section on the line i 7 7 of Figure 1;

Fig. 8 is a detail longitudinal section showing the auxiliary locking device;

Fig. 9 is a detail longitudinal section through one of the tumblers and a part of the key; and" Fig. 10 is alongitudinal perspective section. v

Referencen to these views will now be made by use of'like characters which are employed to designate corresponding parts throughout.

' rlhe invention is described for purposes of illustration in connection with a lock of the tumbler type comprising a body 1 in which a barrel 2 is rotatably mounted. In the present instance however 1t is preferred to insert an insulating sleeve 3 between the body andthe barrel for the purpose of isolating certain parts from electrical contact with each other as will presently appear.

I The body is formed with a series of radial 4 through thesleeve and barrel into a slot 6 1n the barrel, and a follower 7 backed by a spring 8 retained by a plug 9 inserted in the louter end of the aperture. Fn accordance with the usual practice, the tumbler pins are of unequal length, and when received ina key 10 having recesses or depressions 11 of proper depth, bring the planes of partition between the members 5 and 7 into the' plane ofseparation between the body 1 and barrel 2 so that the latter may be turned.

Such a lock is modified for the purpose of the present invention by means of an auxiliary locking device operating on an elec-tric circuit also controlled by the key. This device involves an electromagnet supported on a tube 12 having its ends secured in ears 13 apertures fi, each of which contains a tumbler assembly including a tumbler pin 5 slidable formed on the body of the lock. The coil 14 of the magnet is wound on the tube 12 and has one en-d l5 grounded by attachment to the Jbody which in turn is grounded as indicated by the numeral 16. Current is supplied to the coilfrom a battery 17 having one' terminal grounded as at 18 and the other end joined to one of the tumblers. In order that such electrical connection between the battery and the tumbler may be made to the exclusion of.

other parts of the lock, the sai-d tumbler is equipped with a surrounding insulating sleeve` 19 in whichit moves. rlihe insulating sleeve is extended at 20 to surround the corresponding 'tumbler pin except the tipf thereof and is merged at its upper end into the spring retaining -nut 9 which must also be formed of insulating material. A metallic insert 22 is fitted into the nut and is engaged by a binding post l23 to which is connected the conductor 24 leading from the batter so that the circuit is continued throughA the corresponding spring 8 and tumbler members to the tip of the tumbler pin.

Another tumbler assembly, designated by the numeral 25 is isolated 'from electrical contact with the body in the manner already described and is equipped at its upper end with a binding post 26 to which is connected the remaining-end 27 of the coil 14. It will now be apparent that the circuit ,for supplying current to the coil has a gap between the two insulated tumbler assemblies and is inoperative unless the gap is bridged.

The auxiliary locking device further includes the magnet armature 2 8 which has at p lals.

one end a lug 29 movable through a slot 30 normally forces the lug 29 into the slot 31 and is retracted only when the coil is energzed. The lug thus holds the barrel 2 locked to the body inde endently of the tumblers. The inner end o the barrel further carries a lug 35 which may serve to lock still another device. The auxiliary locking device already described is an adjunct to the key 10 in controlling the movability of the barrel 2 but may however be associated with some device independent of the barrel.

If a key having the proper shape with respect to the tumbler receiving recesses, or in fact having any shape permitting entry for a considerable distance into the slot 6, be in'- vserted in the slot, theinsulated tumblers will be -electrically connected, but the current will also flow from the key to the barrel 2, thence to the body 1 either by direct contact or through the pin 33, and finally to the ground without passing through the magnet nor operating theauxiliary device. It is therefore necessary that the key be adapted to form exclusive electrical communication between the insulated tumblers without permitting the current to be grounded befor passing through the coil. I

In order to satisfy this requirement I insert in the key 10 an insulating bushing 36 joining the points of the particular recesses 11 which are engaged by the insulated tumblers when the key is inserted to its entire extent. In this bushing is provided a conductor 37'^ havin its bare ends exposed at the notched e ge of the key and engageable only by the tips 21 of the insulated tumblers. This arrangement completes the circuit. to the coil by connecting the insulated tumblers,

and further prevents escape of current to the ground 'before passing through the coil. The i ends of the isolatedy conducting path niustbe in the hills or valleys of the keyedge, in order to meet the tips 21.

The positioning of tlie isolated conducting path between the proper points on the key constitutes another factor in the lock combination and doubles the comlplexity of the combination.' Moreover, a ey of given shape is capable of considerable variation merely by altering the position of the ends of the conducting paths, and in this way a single key profile is sullicient to serve a plurality of different locks, whereas in the present practice a single profile is useful for only one lock. It will readily be apparent that the completion of the circuit through the coil/ may be made to depend on the oining of several pairs of tumblers by means of isolated Lacrime conductinopaths in the key, and the complexity o the combination is multiplied by the number of such paths. Inthe event that only one tumbler makes electrical contact with an end of the conducting path, the other end of the path willlobviously be grounded through the body 1.

A lamp 38 is inserted in the conductor 23 between the battery 17 and the first tumbler in order to reduce the current flowing to the coil and thus prevent sparking at the tips of the insulated tumblers.

Although a specific embodiment of the invention has been illustrated and described, it will be understood that various alterations in tlie details of construction may be made without departing from the scope of the in vention as indicated by the appended claims.

'Vhat I claim is:

1. Ina locking device, a body, a barrel rotatable therein, tumblers adapted to lock said barrel to the body, an auxiliary electrically controlled locking device betweensaid body and barrel, a broken circuit connectcdto said auxiliary device, and a. key insertable in said barrel and adapted to complete said circuit.

2. In a locking device, a b0dy,`a barrel rotatable therein, tumblers adapted to lock said barrel to thebody, an auxiliary electrically controlled locking device between said body and barrel, a circuit for supplying current to said device, said circuit passing through at least one of said tumblers and having a gap at said tumbler, anda key insertable in said barrel for engagement with said tumblers and adapted to closesaid gap.

3. In a locking device, a body, a barrel rotatable therein, tumblers adapted to lock said barrel to the body, an auxiliary electrically controlled locking device'between said body and barrel, a circuit for supplying current to said auxiliary device, said circuit including two of saidl tumblers and being open between said tumblers, and a key insertable in said barrel and adapted to make electrical connection between said tumblers.

4. In a locking device', a body, a barrel rotatable therein, tumblers adapted to lock said barrel to the. body, an auxiliary electrically lcontrolled locking device between said body and barrel, acircuit for supplying current to said auxiliary device, said circuit including two of said tumblers and beinfr open between said tumblers, and a key liaving an isolated conducting path adapted to make electrical connection between said tumblers.

5. In a locking device, a body, a barrel rotatable therein, tumblers adapted to lock said barrel to the body, an auxiliary electrically controlled locking device between said body and barrel, a circuitior supplying current to.said auxiliary device,- said circuit includiml ing two of said tumblers and being Open be- I tween said tumblers', and a key insertable in said barrel aridhavingdepressions adapted to receive the ends of said tumblers, said key having an isolated conducting path joining the depressions corresponding to the tumblers contained in said circuit.

6v In a locking device, a body, a barrel rotatably mounted-therein, tumblers adapted to 'lock said barrel to the body, an auxiliary electrically controlled locking device, a broken circuit inclndin said auxiliary device, and a key insertab e in said barrel and adapted to complete said circuit.

7. In a locking device, a body, a barrel rotatable therein, tumblers adapted to lock said barrel to the body, an electromagnet mounted on said body and having an armature slidable therein, a keeper member 'Ixed to said barrel and adapted to receive said armature; a spring device normally projecting the armature into thevkeeper member, a broken circuit including said magnet, and a key adapted to comp ete said circuit.

8. In a locking device, a body, a-barrel r0- tatable therein, tumblers adapted to lock said circuit lncluding two of said tumblers and y being open between said tumblers, and a key inscrtable in said barrel and having an isolated conducting path adapted to make electrical connection between said tumblers.

In testimony whereof I aix my signature.

'GLENN w. WATSON. 

